A man from Hove suffered serious facial injuries requiring extensive treatment in hospital at a party in Lewes at the weekend.
The 31-year-old man was taken to the Royal Sussex County Hospital in Brighton after being attacked at about 4.30am on Sunday (16 March).
The took place at the Skate Park, a warehouse premises in Phoenix Place, Lewes.
A 22-year-old man from Lewes was arrested on suspicion of assault causing grievous bodily harm.
After being interviewed he was released on police bail until Friday 9 May while inquiries continue.
Anyone who saw what happened is asked to phone Sussex Police on 101, email 101@sussex.pnn.police.uk or contact the independent charity Crimestoppers anonymously on 0800 555111.